1. Technical Field
The present disclosure relates to a PLC apparatus and more particularly, to a PLC apparatus which is capable of predicting its life expectancy depending on an ambient temperature of the PLC apparatus.
2. Description of the Related Art
Automated facilities in traditional industrial sites include mechanical equipment using relays and so on. However, changing the functionalities of the automated facilities composed of the mechanical equipment had a difficulty of manually altering wirings of internal circuits of the automated facilities. A PLC (Programmable Logic Controller) is a device contrived to avoid such a difficulty.
The PLC is a logic controller which can be programmed. In general, the PLC acting as a computer receives a signal from a machine, processes the signal according to internal programmed contents, and outputs the processed signal to the machine. The PLC may be obtained by replacing the functions of control devices such as a relay, a timer, a counter and so on with semiconductor devices such as ICs (Integrated Circuits), transistors and so on. The PLC is capable of program control by an arithmetic operation function added to an essential sequence control function and performs a predetermined logic according to a program stored in its internal memory. The PLC can be applied to a variety of tasks such as device control, device numerical setting, time control, real-time monitoring, real-time data collection, safety device operation and so on.
In this way, the PLC is being widely used in a variety of industries and has different use environments. Therefore, the PLC may have different life expectancies. In addition, the PLC may be used under hot and humid environments or under cold environments. Therefore, since a user cannot correctly know a PLC available time, the user cannot confirm part exhaustion and damage until the PLC breaks down.
Although product life is in general specified in a user's manual of the PLC, since a user may not know when the PLC begins to be used, and cannot predict PLC exhaustion and breakdown in use, the overall system may have a big problem due to an unexpected to PLC breakdown.
Therefore, there is a need to predict the PLC life and take an active measure before the PLC breaks down.